Prostate diseases such as prostatitis, benign prostatic hypertrophy, prostatodynia, and prostate carcinoma afflict many adult males. The largest population of men stricken with prostate problems are those over age fifty. However, inherited prostate problems can appear in much younger men.
Prostatitis is generally an inflammation of the prostate gland and the surrounding tissue. Several causes of inflammation are known and have been categorized by the National Institute of Health. Category I is recognized as acute bacterial prostatitis. Category II is chronic bacterial prostatitis. Category III includes chronic abacterial prostatitis and CPPS (Chronic Pelvic Pain Syndrome). Category IIIA is inflammatory CPPS, and Category IIIB is non-inflammatory CPPS. Finally, Category IV encompasses asymptomatic inflammatory prostatitis.
Category I, acute bacterial prostatitis, has been quite effectively managed in the past using a wide spectrum of antibiotics. Category II, chronic bacterial prostatitis, is most often treated with higher potency drugs for management such as Quinolone or Trimethoprim therapy for as long as needed. Attempts at treating Category IIIA, inflammatory CPPS, have been made using a wide variety of antibiotic and anti-inflammatory agents.
Administration of treatment substances through the bloodstream has been less than satisfactory in treating prostate diseases. Large doses of treatment substance have been required for effective treatment. Therefore, it is now believed that a filtering barrier exists between the prostate and the body's blood supply which prevents treatment substances from entering the prostate. The problematic effect of this barrier is two fold. First, the barrier prevents most of the treatment substance dosage from entering the prostate and having a therapeutic effect. Second, the barrier mandates extremely high doses of the treatment substance in order to have a therapeutic effect. Since most of the drug is not allowed into the prostate it remains in the body's general circulation. This results in many undesirable side effects.
In an attempt to reduce the need of high doses of strong antibiotics and other treatment substances, many urologists have turned to injecting treatment substances directly into the prostate. Although this procedure has yielded greater therapeutic results at much lower doses, frequent repetition of injections is generally required to obtain adequate treatment results. This frequent injection repetition causes much pain, discomfort, and inconvenience to the patient.
Benign prostatic hypertrophy is a condition where the prostate over-grows or becomes enlarged. Prostate growth is controlled by androgen receptors found in the prostate gland. When the androgen receptors are stimulated by 5 .alpha.-dihydrotesterone (DHT), they cause the prostate to grow. DHT is produced by an enzymatic conversion of testosterone in the prostate.
The main treatments for benign prostatic hypertrophy have been drug therapy and surgery. Transurethral resection of the prostate (TURP) is the most widely used surgical treatment procedure. The most widely used drug therapy has been the bloodstream administration of an .alpha.-blocker such as terazosin or doxazosin. Additionally, bloodstream administration of a 5 .alpha.-reductase inhibitor such as finasteride has been used. These drugs, however, often have the undesirable side effects of postural hypotension or impotence, and decreased libido. Additionally, these drugs must be continually administered for the duration of the patient's life in order to prevent a return of the problem.
One new method of treating benign prostatic hypertrophy is the intraprostatic injection of a collagenase, hyaluronidase mixture. This mixture effectively dissolves prostatic tissue which has the ultimate effect of shrinking the prostate. However, since this treatment does nothing to prevent further prostate growth, the treatment must reapplied as frequently as new prostate growth demands.
Prostate carcinoma is a neoplasm which most frequently affects men over 50 years old and is a leading cause of cancer deaths in men. Radical prostatectomy or surgical removal of the prostate, and radiation therapy are the most common treatment methods for prostate carcinoma. However, radical prostatectomy often results in impotence and urinary incontinence. Radiation therapy, while having a somewhat lower cure rate than surgery, is generally well tolerated. However, radiation therapy has also been known to produce impotence, incontinence, cystitis, and proctitis.
In addition to surgery and radiation therapy, other methods for treating prostate carcinoma have been employed. One such method is the intramuscular or subcutaneous injection of a sustained release depot formulation which contains LHRH agonists. This method is not without adverse side effects, such as prolonged systemic exposure to high doses of the formulation. Another, more recent treatment method is the intraprostatic or intralesional injection of alpha interferon. This method too has the unfortunate requirement of frequent repetitive injections over a substantial period of time.
In view of the foregoing, a method of treating prostate diseases and disorders which minimizes adverse side effects as well as a patient's pain and discomfort is highly desirable. Further, a method of treatment which allows effective therapeutic results with lower doses of the treatment substance is desirable. Additionally, a method of treatment which produces a sustained delivery of the treatment substance over long periods of time is desirable.